/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.lock;

import java.util.HashMap;
import java.util.Map;

import org.apache.jackrabbit.webdav.DavConstants;
import org.apache.jackrabbit.webdav.xml.DomUtil;
import org.apache.jackrabbit.webdav.xml.Namespace;
import org.apache.jackrabbit.webdav.xml.XmlSerializable;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

/**
 * The <code>Type</code> class encapsulates the lock type as defined by RFC
 * 2518.
 */
public class Type implements XmlSerializable {

	private static Map<String, Type> types = new HashMap<String, Type>();

	public static final Type WRITE = Type.create(DavConstants.XML_WRITE,
			DavConstants.NAMESPACE);

	/**
	 * Create a <code>Type</code> object from the given localName and namespace.
	 * 
	 * @param localName
	 * @param namespace
	 * @return <code>Type</code> object.
	 */
	public static Type create(String localName, Namespace namespace) {
		String key = DomUtil.getExpandedName(localName, namespace);
		if (types.containsKey(key)) {
			return types.get(key);
		} else {
			Type type = new Type(localName, namespace);
			types.put(key, type);
			return type;
		}
	}

	/**
	 * Create a <code>Type</code> object from the given Xml element.
	 * 
	 * @param lockType
	 * @return <code>Type</code> object.
	 */
	public static Type createFromXml(Element lockType) {
		if (lockType != null
				&& DavConstants.XML_LOCKTYPE.equals(lockType.getLocalName())) {
			// we have the parent element and must retrieve the type first
			lockType = DomUtil.getFirstChildElement(lockType);
		}
		if (lockType == null) {
			throw new IllegalArgumentException(
					"'null' is not valid lock type entry.");
		}
		Namespace namespace = Namespace.getNamespace(lockType.getPrefix(),
				lockType.getNamespaceURI());
		return create(lockType.getLocalName(), namespace);
	}

	private final String localName;

	private final Namespace namespace;

	/**
	 * Private constructor.
	 * 
	 * @param name
	 * @param namespace
	 */
	private Type(String name, Namespace namespace) {
		this.localName = name;
		this.namespace = namespace;
	}

	/**
	 * Returns <code>true</code> if this Type is equal to the given one.
	 * 
	 * @param obj
	 * @return
	 */
	@Override
	public boolean equals(Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj instanceof Type) {
			Type other = (Type) obj;
			return localName.equals(other.localName)
					&& namespace.equals(other.namespace);
		}
		return false;
	}

	/**
	 * Returns the Xml representation of this lock <code>Type</code>.
	 * 
	 * @return Xml representation
	 * @see org.apache.jackrabbit.webdav.xml.XmlSerializable#toXml(Document)
	 */
	public Element toXml(Document document) {
		Element lockType = DomUtil.createElement(document,
				DavConstants.XML_LOCKTYPE, DavConstants.NAMESPACE);
		DomUtil.addChildElement(lockType, localName, namespace);
		return lockType;
	}
}